FS#10 - Add generic key=value preference system

There are a lot of places where we could use the ability to arbitrarily store data points; things like custom fields for images, raw decode parameters (they're always changing!), or per-album/folder sort order (for things like subalbums, not just images!)

In any case, I'd definately like to see things like the image processing options moved out of their rigid, fixed database table.

Closed by Solomon Peachy
2007-02-09 00:03Reason for closing: ImplementedAdditional comments about closing:
Another old, old ticket implemented!
key=value across the board, and
eliminated four tables in the process!

The unification of the session lookup code has already started to rope in a few preferences. Once the new session stuff is completed, we can extend that code to look up the preference data too, and alter all pages to use that data instead of looking it up themselves.

Once the lookup/sets are centralized properly, we can much more easily move to a key=value model, as it'll just mean modifying code in one place for *all* lookups, and of course the pages that actually write preferences too.